1. Field of the Invention
The present invention relates to a method and apparatus for detecting discharge defects in a liquid discharge head used in an ink jet printer or the like, a computer-readable recording medium, and a printing system using the detection technique.
2. Description of the Related Art
Regarding a technique of detecting a discharge defect in an ink jet head having a plurality of liquid discharge ports (nozzles), JP2010-240885A discloses a method of comparing image data (reference data) as a comparison reference for quality determination with read data, which is obtained by reading a printed image with a scanner, and detecting a discharge defect of a nozzle from the difference between the pixel values of both the data items. JP2010-240885A discloses: causing a scanner to read an image, which is drawn on paper by discharging ink from a nozzle while moving a head unit and the paper relative to each other based on image data for printing, in a resolution that is lower than the resolution of the image data in the relative movement direction of the head unit and the paper; generating reference data having the same resolution as the resolution in the relative movement direction in the read data, based on the image data; and detecting a nozzle defect by comparing a plurality of read data pixels in the same pixel row in the relative movement direction on the read data with a plurality of reference data pixels, each corresponding to the plurality of the read data pixels.